    [Patent document 1] JP-2006-184219 A    [Patent document 2] JP-H7-128423 A    [Patent document 3] JP-2007-159106 A (U.S. Pat. No. 7,358,896 B2)
For example, a GPS receiver is provided which receives a satellite signal from a GPS satellite to perform positioning (for example, refer to Patent document 1). According to the technical idea described in Patent document 1, when acquiring a satellite signal from a GPS satellite, a temperature compensation oscillator is used as a transmission source of a reference frequency of an oscillator. A frequency offset is amended by using the temperature compensation crystal oscillator as a local oscillator; a GPS signal is received.
Further, a GLONASS receiver is provided. The GLONASS system includes 24 satellites. Herein, 21 of them transmit satellite signals at present; the satellite signals are received by a receiver, performing positioning. A reception apparatus which is shared between the GPS and the GLONASS is developed (for example, refer to Patent document 2). According to the technical idea described in Patent document 2, a frequency conversion from RF to IF is realized using a single mixed means (mixer etc.); components, which have an image relation from a viewpoint of a frequency of a local oscillated signal, are mutually separated from a mixed signal to output, intending to eliminate interference with a positioning signal concerning each positioning system.
According to the technical idea described in Patent document 3, a multi-band receiver for global positioning system satellite system (GNSS) is provided to be a system which uses, in an integrated manner, Global Positioning System (GPS) employed in the U.S., Global Navigation Satellite System (GLONASS) employed in the Russian Federation, and Galileo Positioning System made by the European Union.
When intending to make the positioning function highly precise by combining the function of a GPS receiver and the function of a GLONASS receiver, a positioning is performed by acquiring the satellite signals of both the functions using the oscillated frequency which the local oscillator oscillates. However, the inventor confirms that even in such a positioning, both of the functions cannot be operated favorable.